Timing device for power transmission systems



Aug. ,10, 1943. H.` F. vlcKERs TIMING DEVICE FOR POWER TRANSMISSION SYSTEMS Filed Jan. 27, 1940 8 sheets-sheet 2 Y 6AM,

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TIMING DEVICE FOR POWER TRANSMISSION SYSTEMS Filed Jan. 27, 1940 8 Sheets-Sheet 5 l 'l F1 'o "3Q, JW

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f1943.` H. F. vlcKERs TIMING DEVICE FOR POWER TRANSMISSION SYSTEMS Filed Jan. 27, 1940 8 .'Sheets-Shee'tl 6 l v. I

Aug. l0, 1943. H.,F. vlcKERs 2,326,184

TIMINCT DEVICE FOR POWER TRANSMISSION SYSTEMS Filed Jan. 2.7-, 1940 8 Sheets-Sheet '7 Aug. 10,1943., H. F. vlckERs 2,326,184

TIMINGIDEVICE FOR POWER TRANSMISSION SYSTEMS Filed Jan. l 27, 1940 8 Sheets-Sheet 8 ATTORNEYS Patented Aug.y I0, 1943 `UNITED STATES PATENroFFlcE TmiNG DEVICE'Foa POWER 'raANs- MISSION srs'rEMs I Harry F. Vickers, Detroit,. Mich., assignor to Vickers, Incorporated, Detroit, Mich., a cor-- poration of Michigan A Application January 27, 1940, Serial No. 315,889

(ci. sof-s) r is claims.

This invention relates to timing devices for power transmission systems and has particularly in which it is the practice to have a slow moving drive shaft and an output shaft which makes several revolutions to one revolutionof the drive shaft, it will be seen that a small deviation in `the timing device at, the drive will be greatly multiplied at the' output. In many cases the timing controlmust ,be connected to the drive and consequently it is essential that it be accurate.

It is a further object of the present invention to provide a timing arrangementin which the output shaft of a control system may be stopped within a ww degrees -of the same point in each cycle. A11A added feature of the device is that it may be adapted to practically any type of power system and certain objects of the invention have to do with the combination of the basic timing control with various hydraulic p'ower systems.

Briefly, the invention consists of introducing intoja hydraulic circuit two or more interconnected timing valves which are actuated from a power shaft. These valves are preferably arranged to be shifted by said shaft at different rates of movement so thatvat one particular point in a cycle of movement, each of the valves will have reached a deiinite control position which will produce aresponse in the system and cause a change in the operation of the driving Shaft. This change may either be a stopping or a reversal or, in some cases, it might be simply a change in speed. The present invention is parillustrating the passageways in a single plane for purposes of disclosure and showing the timing control.

Fig. 2 is a sectional view on the lines 2-2 of Fig. l. j

Figs. 3 and 4 are additional-views of the system of Fig. 1 showing the parts in different relative positions. f

Fig. 5 is a sectional view of a hydraulic system in which a pressure backed relief valve is utilized i to control a pressure source and the timing control valves of the present invention are used in cooperation therewith.

Fig. 6 is a view similar to Fig. 5 showing the parts in different relative positions.

Fig. 7 is a partial view of the device shown in Fig. 5 illustrating a valve in a shifted position.

Figs. 8 and 9 illustrate the invention embodied in a hydraulic control system in which a directional control valve is utilized, the timing -control being arranged to effect an automatically' oscillating cycle in the shifted member.

Figs. 10, 11 and 12 illustrate various portions of the system shown in Figs.. 8 and 9 with the l showing a valve in its respective positions.

ticularly'useful in devices having long or continuous operation in winch the oil eats and be-4 comes thin. With a single coun r-valve control, as the, valve approaches stop position there may be leakage which will cause premature stopping or change of direction. With the provisionl of a tripper valve as well, as the counter valve, the tripper serves as a. check orseal for which the change in actionshould take place.

' Fig. 1 is a secuoiiai view of a. hydraulic circuit,

Fig. 20`is a partial view of Fig. 17 showing the relationship of the control valves during a part of the cycle.

Figs. 21 and 22 .illustrate the invention embodied in a system in which the power element is `controlled by a. variable displacement pressure source.

Aniliustrative embodiment of the invention is vshown in Figs. 1 to 4. VReferring to these figures, it will be seen that a pump 25 furnishes liquid under pressure to a motor 26 through a pressure conduit 21. The motor 26 is mounted in the side of a tank 28 which ls adapted to contain liquid,

usually oil, to be used in the pressure system. A

y drive shaft 29 ofthe motor passes through the tank 28 and is mounted at its outer end in a bearvalve block 33 mounted on the top of the tank. r

1n this valve block are three valves u, as and n. The valve 34 may be designated as a. means for provided with a notch 51. provided with a dog-end 59 which may be revceived by the notch 51. age a piston 66 is connected to the belLcrank 58.

controlling the operation of the motor 26 since it is shiftable from a position shown in Fig. 1 to a position shown in Fig. 4 to' block the -ow of liquid from the conduit 32, this flow normally passing to a tank conduit 31. A spring 38 urges the valve 34 to its closed position shown in Fig. 4. When the valve 34 is shifted to its closed position, locking the tank conduit 31 from the exhaust conduit 32, the pump will deliver pressure to the tank through the relief valve 39. The valve 34 is also adapted to be controlled by pilot pressure which has its source in a. conduit 48 leading from conduit 21. This conduit 40 leads through a needle valve 4| to a chamber 42 above thev valve 34. Pressure in this chamber will shift the valve 34 to its open position as shown in Fig. 1.

Valves 35 and 36 are provided to control the pilot pressure in chamber 42. Each of these valves is adapted to have an open and closed position. When the valve 35 is in its open position, as shown in Fig. 1, it will connect a conduit 43 leading from chamber 42 to a conduit 44 leading to valve 36. When the valve 36 is in open position, as shown in Figs. 3 and 4, the conduit 44 will be connected to a conduit 45 leading to the tank. It' will thus be seen that when both'valves 35 and 36 are in open position, the chamber 42 -will be open to the tank thus relieving the pressure therein. 'I'his will permit spring 3S to shift the valve 34 to its closed position.

Valves 35 and 36 are each arranged to be shifted by cams 46 and541, respectively. Cam 46 is operatively connected to -shaft`29 by a screw 48 which is arranged to revolve the cam 46 once in a predetermined number of revolutions of the shaft 29. .Thecam 41 is operatively connected to the shaft 29 by a screw 49 which is arranged to revolve cam 41 once in every revolution of the shaft 29. Springs 56 and 5| urge the valves 35 and 3.6 respectively against the cams. Each of the Valves is provided, respectively, with a. follower 52 and 53. A lever 54 pivoted at 55 serves to permit manual operation of the valve 36 in a manner which will be later described. Suitable conduits are provided to vent the ends of valves 35 and 36. f

A latching means for the shaft 29 is also arranged to be controlled by pilot pressure. This means consists of a wheel 56 (Fig. 2) which is A bell crank 58 is Through suitable link- The piston 66 is located-in a cylinder 6| and a spring 62 urges the piston to thel left as viewed in Fig. 2. The left end of the piston 60 is connected. by a conduit 63 to conduit 43 so that Athe pressure in the chamber 42 will at all times, be

exerted on the piston 60. It will be understood that the parts above described in 'connection with the latching or locking means 56 and 5 9 may be formed with suicient strength including the spring 62 so that the motor will be locked in P0- sition when pilot pressure is not exerted against the piston 60. The requirements of the particular transmission system will determine the strength which these parts will be formed for.

In the operation of the device above described,

assuming that the parts are in the positions shown in Fig. 4, the pump 25 will be by-passing.

pressure through the relief valve 39 and the pilot pressure which is maintained in the conduit 21 will be passing through the needle valve 4| and to the tank through conduits 43, 44, and45. To start the motor, the operating lever 54 must be moved to its top position shown in dotted lines. This will shift the valve 36 upward so that the conduit 44 will be cut oif from conduit 45 and from the tank. Pressure will then build up in the chamber 42 and also in the conduit 63 and cylinder 6|. When this pressure has .reached a predetermined point, valve 34 will be shifted against the spring 38 to the position shown in Fig. 1 and the piston 66 will be shifted against the spring 62 to the position shown in Fig. 2, thus permitting the dog 59 to be withdrawn from the notch 51.

As soon as the valve 34 is shifted by the pilot pressure in chamber 42,` the exhaustl conduitl 32 of motor 26 will be open to the tank and the motor will be operated by pressure from the pump. The valve 36 must be held in its upper position for a certain length of time to maintain )conduit 45 blocked until a cam portion 46a on cam wheel 46 is shifted out from under the follower 52. This will permit the spring 50 to shift the valve 35 to its closed position, as shown in Fig. 3. During each revolution of the shaft .29, the valve 36, which may be called a tripper valve, will be shifted by cam portion 41a on cam 41 from the position shown in Fig. 1 to the posi-v tion shown in either Figs. 3 or 4. After a predetermined number of revolutions of the shaft 29, depending on the ratio of the connection between the shaft and the cam 46, the valve 35, which may be called a. counter valve, will also be shifted by cam portion 46a to its open posi- "tion, as shown in Fig. 1. In Fig. 1 the cam wheels 46 and 41 are in motion and nearing the end of a cycle. It will be seen that the cam member 46a has reached its top. position and the cam 41 is approaching its top position.' As yet, the tank line 45 is cut off from the line 44 so that the chamber 42 is still cut oi from the tank. As soon -as the cams are moved to the respective lpositions shown in Fig. 4,- it will be seen that have arrived at their Fig. 4 position, the pressure in line 63 and chamber 42 has been released, and valve 34 has been moved upwardly by spring 38 to thus close oil' passage 31. By the release of pressure in line 63, 4spring 62 has moved piston 60 to the left to oscillate lever 58 to the left. At A this timeth e notch 51 of wheel 56 is in such a positionthat dog-end 59 will engage therein.

As the parts are viewed in Fig. 3, the mechanism is shown in operation with the follower 52 riding on the wheel 46 and the valve 35 in closed position. As will be understood from the above description the valve 3'6 reaches the open, position shown in Fig. 3 once in every revolution of the shaft 29.

In Figs. 5, 6 and 7,. there is illustrated the combination of the above described timing control withaI system 'in whichv a hydrostatic relief valve is utilized. In this system a pump 10 furnishes liquid under pressure to a, feed conduit 1| which leads to a directional control valve 12. This valve has two ports openingrespectively to conduits 13 and 14 which, in turn, lead to a reversible motor -15. Tank outlets 16 and 11 also open to ports surrounding the valve and lead to a tank connec- `tion 18.

V19 which may be closed by .a hydrostatic valve i8|).

pressure liquid to the tank when it reaches acertain predetermined limit. The feed line 1| is connected to the pressure chamberl 83, in this case, through a restricted opening 85 in the piston 8| so that it may be said that the pressure chamber 83 receives pilot pressure from the feed line through the restrictedorice 85.

In this system, shown in Fig. 5, the controlling element for the operation of the system is the valve 80 which, when backed by pressure in chamber 83, will maintain the bypass conduit 19 closed and thus vpermit pressure to be directed from the pump to the motor 15 through the directional control valve 12. It will be seen that the directional control valve may be shifted .to direct pressure t that pressure cannot reach the chamber 83 through the' restriction 85 as fast as it can pass through the venting lines as above described. The opening movement of the valve 80 (Fig. 6) will bypass the ow from the pump 10 through lin'e 19. The operation of the latching means 58 is the 'same as described in connection with Fig. 2, the pressure against piston 60 being dependent on the pressure in the chamber 83. The preseither line 13 or 14 and thus control the direction Y of rotation of the motor. The motor in this case drives a shaft 86 'and is mounted in a tank 28a in the top of which is a' valve housing 33a. 'Ihe shaft 86 passes through the wall of the tank and is provided with a locking wheel 56 as in connection with the embodiment of Fig. 1, with suitable latching means being shown as described in connection with Fig. 2. The conduit 63 for controlling the piston 60 of the latching means is connected in Fig. 5 to a conduit 81 which leads from the pressure chamber i83 to a control valve 88 located in the housing 33a. A second control valve 89 is also located in the housing. The pressure chamber 83 isadapted to be bypassed to the tank through thepconduit 81, past the valve 88, through a' conduit 90, and past the valve 89 to a conduit 9|. The valve 88 has an open position as in Fig. 5 and a. closed position as in Fig. 7. Similarly valve 89 has aclosed position as in Fig. 5 and an open position as shown in Fig. 6. The valve l88` is also arranged to restrict the exhaust flow through the tank conduit 18 'as it passes to line 92. This will cause deceleration of the motor 15 and it will vbe seenthat this restriction takesplace as the valve is moved to its open position as above described.

The operation of the system shown in Figs. 5 and 6 issimilar to that disclosed in connection with Fig. l'. The counter valve 88 and the tripper valve 89 are shown as being operated by the shaft 86 through worm gears 48 and 49 operating cam wheels 48 and 41, respectively, with a one to one ratio between the shaft 88 and the cam 41 and a predetermined ratio between the shaft 86 and the cam 46. As the parts` are shown in Fig( 5, the motor has been operating by receiving pressure from pump 10 through line 1|, valve 12 and `line 14. Tank flow from the motor is passing through line 13, valve 12 and line 18. As the valves are shown, valve 88 is moved to its open position and is gradually restricting the flow from line 18 to line 92, thus causing a deceleration of the motor. Slits 93 are provided in the valve 88 to permit this gradual restriction in the exhaust flow. At this time ,the

or vented through lines 81, 90 and 9| and the pressure in the feed line 1| will move the Apiston 8| upwardly. This movement is due to the fact sure in the entire system is limited by the valve 84, which will open ata predetermined point. The operation of the system is the same if the valve 12 is shifted to the right so that pressure from line 1| may reach the line 13. The operation of the motor will then be reversed but the timing arrangement will function in the same' manner. 4The system may be started by raising the valve 89 with the lever 54.

' In Figs. 8 through 12 is illustrated a hydraulic control system in which the invention has been arranged to effect automatic oscillating cycles. In this system a pump |00 furnishes liquid through a conduit |0| to a directional control valve |02 which invturn directs liquid to a reversible motor |03 through eitherconduit |04 or |05 depending on the position ofthe control valve |02. If pressure is being directed to conduit |05, as in Fig. 8, exhaust pressure will be delivered from conduit |04 through the control valve |02 to a tank conduit |06. If the valve |02 is shifted as shown in Fig. 9,- pressure will be directed through conduit |04 to the reversible motor and exhaust liquid will fiow from conduit |05 to tank conduit |06. The operation of the the entire system is to be controlled by a. manually operated valve |01 controlled by hand lever |08. A bypass valve is provided, as before in Fig. 5, and the chamber83 of this valve is connected through a. conduit |09 to the valve I 01. When the valve |01 is in the position shown in Fig. 8, conduit |09 is blocked from the tank but when valve |01 is shifted to the position shown in Fig. 12, conduit |09 will be open to a tank conduit ||0 thus relieving the pressure in chamber 83. A relief valve 84 is also hydraulically connected to the chamber 83. Relieving of the pressure in chamber 83 will permit thepressure in conduits |0| to open the valve, as shown in Fig. 12, and thus bypass liquid under pressure to thetank through a conduit At the respective ends of valve |02 are formed chambers ||2 and I3 for receiving pilot pressure to cause shifting of the control valve |02.

Counter valve ||4 and tripper valve |5 are used to control the system. The control valve ||4 is arranged to be shifted to direct pressure to either'a conduit I8 leading to chamber ||2 or a. conduit ||1 leading to chamber ||3. Pressure in these conduits is received from a conduit ||8 leading from the valve ||5 and pilot pressure is connected to the valve H5 by a conduit 9 leading from pressure conduit |0|. Witlf the valve H5 in the position shown in Fig. 8, pressure is blocked in conduit H9 so that it may not pass to conduit I I8 and to the valve I5. If, however, the valve I |5 is moved to the position shown in Fig. 9, the pressure may pass from the conduit ||9 to conduit H8 in the valve ||4. Each of the valves ||4 `and ||5 is provided with a follower |20 and |2|, respectively.-` The follower |20 rides on a cam |22 which is driven through a shaft |23 and a screw 48 and wheel |24 froma motor shaft |25.v Similar1y,ithe followerV 2|- rides on a cam |28v which is driven in .acne to. one'ratio from :shaitl'ii by a screw 49. Acam portion I28a. is

formed on the cam |26 to cause a lifting of the valve ||5 to the position shown in Fig. 9, once in every revolution of shaft |25.

The cam |22 has a peculiar shape. It will be noted` that a portion of the cam is circular. Another portion has a projection |21 which projection will serve to move the valve ||4 to the positionsnshown in Figs. 8 and 9. A recessed portion |28 is also provided and when the follower is on this portion, the valve ||4 will be in the position shown innig. 1o. when the i01- lower is on the circular portion of the cam, the valve ||4 will be in the position shown in Fig. 11.

With the cams and the valves in the position shown in Fig. 8, it will be seen that the projec tion |21 on cam |22 has just shifted the counter" valve ||4 to` the position in which pressure may pass from conduit ||8 to conduit ||1. Tripper valve Il I5, however, is still in a position where pilot pressure is blocked from conduit ||8. As soon as valve ||5 is move'd by cam portion |26a to the position shown in Fig. 9, pilot pressure maypass from conduit ||9 to conduit ||8 and thence past valve ||4 to conduit ||1'and chamber ||3. This will cause a shifting of valve |02 to the right and, consequently, the

- direction of ilow of motor |03 will be reversed.

At the end of the next cycle the follower |20 will be on the recessed portion |28 of cam |22 as viewed in Fig. 10. At this time, the conduit ||8 is open to conduit 6 whichleads to chaml At a certain time in the revolution of ber ||2. shaft |25, the valve ||5 will be shifted to the position shown in Fig. 9, at the same time as the valve ||4 is in the position shown in Fig. 1'0. Pilot pressure may then lpass from conduit to conduit H8 and conduit ||6 and thence to chamber ||2, again shifting the valve |02 to the position of Fig. 8. This oscillation will continue until the lever |08 is moved so that the chamber 83 of valve 8,0 is vented. The system will then stop. It will thu's be seen that an automatic oscillating cycle has been provided and the cam 1|22 willbel geared to the shaft |25 in such -a '45 pump output. At the same time conduit |45 is way that a predetermined number of revolutions will take place during the time that the cam is passing from a position such as shown in Fig. 8, to a position shown in Fig. 10.

In Fig. 13, the invention' is shown adapted to a hoisting system. In this system, a hoisting motor |30 is to be driven in a hoisting movement by pressure from a pump |3|. On a motor shaft |32 is located a hoist wheel |33. A cable |34 wraps around this wheel |33 and supports a weight |35 to be lifted and lowered. At the other end of the shaft |32 is a brake drum |36 and a screw |31. A brake member |38 is adapted to contact the drum |36 to hold the shaft |32 from rotating. This brake member is connected to a piston |39 and is urged toward the drum 5. Pilot pressure is derived from conduit |45 and .the restriction 85 in the valve. Conduit |45 also leads to a directional' valve indicated gen-` The motor |30 is connected to the valve |41 by conduits |48 and |49. Pilot pressure for controlling the system is directed from a conduit |50 connected to chamber 83 to the valve |41. Another control valve has conduits |52 and |53 leading also to the valve 5 |41. A follower |54 on valve |5| rides on a cam |55 which is geared tothe shaft |32 in a one to one ratio.

An extension |56 on valve |41 has a slidable member |51 thereon, the movement of which is l0 limited by adjustable nuts |58 and |59. The

member |51 is connected through a lever |60 to a nut |6| which screws on the screw member |31.

It is believed that the details of the valves |41 and |5| can best be brought out by describing l5 the operation thereof in connection with the system. As the parts are viewedin Fig.,13, the equipment is hoisting the weight |35 and nearing the end of the hoisting movement.` Pressure is ilowing from conduit |45 to the conduit |48 as may be clearly viewed in Fig. 16. As the hoisting movement reaches completion, it will be seen' that the movablefmember |51 is being shifted to the left, Fig. 13', and the valve |41 is following this movement caused-by rotation of the screw |31 in the nut IBI. At theparticular point illustrated in Fig. 13, it will be seen that,

` while pilot pressure may pass from conduit |50 to conduit |52, past a restriction in valve |41,

pilotpressure may not pass to conduit |53 be- 3o cause of the position of valve |5|.' Conduit |53 is connected to a tank conduit |62. Meanwhile, -tlie ow from conduit |45 is .gradually being cut olf from conduit |48 and the valve |41 is provided with slots A|63 to permit restricted iiow. Valve 1 80, in connection with relief valve 84, is an effective relief valve which'will permit by-passing of a certain amount of volume from pump |3| as the passage from line |45 to |48 is gradually restricted. As the hoisting movement comes to an end the cam |55 will shift the valve |5| downward so that conduits |52 and |53 are connected. This will permit a venting of chamber 83 and, consequently, pressure in conduit |45 will open valve 80 and cause a by-passing of closed from .conduit |48 by valve |41 to prevent lowering.

It will be seen at this time that as soon as chamber 83 is vented, the conduit |4|, connected to conduit |50, will also lbe vented thus permitting spring |40 to move the brake memberA |48 against drum |36. The line |53 is closed, as shown in Fig. 16, when lever |64 is in hoist position. However, at the end of the hoisting, the entire valve will be shifted so that this line is open simultaneously with the by`passing of lines |50 and |52.

To eect a lowering movement of the motor |30, the valve |41 is shifted to the left by a manually operable lever |64. This position is shown in Fig. 14. At this time it will be seen that a branch conduit |65 leading from conduit |48, is connected to conduit |49 so that liquid coming from the motor in its reverse movement may pass G5' again into Conduit |49. During this cycle the motor functions as a pump and a low pressure foot valve |66 resists the return of oil to the tank thus constraining' the circulation of oil to the 7U motor circuit during the lowering cycle. With-'- out this foot valve a partial void would tend to operate in the system and irregular operation would result. The shifting of valve |41 to the position shown in Fig..14 will cut oY conduit |50 from conduit |52 but willfconnect it to avrelief v will take place.

valve I 61. This relief valve is set to sustain pressure in conduit |50 just sufficient to cause releasing of the brake member |38. However, the valve |61 will still permit tank ow at a greater rate than flow may take place through restriction 85 of valve 80 so that the pump |3| is unloaded at this time.

During the lowering operation, the valve |41 will remain in its lower position (Fig. 14) until the movable member |51 is shifted to the right to contact nut |59; there will then be a movement of the valve |41 to the right gradually restricting and finally blocking the flow through conduit |65, thus bringing the hoisting' motor |30 to rest. The final movement of valve l|41 will again connect the conduit |50 with conduit |52 and the timing valve ||so that chamber 83 is again vented aba predetermined point in a revolution and consequently, cause a building up of pressure in the hydrostatic chamber'83. Consequently, pump |3| may again deliver liquid from conduit |45 to conduit |48 and simultaneously the brake |4| will be released.

In Fig. 17, `the invention isshown embodied in a` hydraulic system which is reversible and in which the timing control maybe used for movements in both directions. Referring to Fig. 11,v a motor |10 drives a main pump |1| and a pilot pump |12. The main pump |1| is adapted .to furnish pressure to a reversible motor |13 througha conduit |14 andl conduits |15 and |16. A directional control valve |11 is' interposed in these conduits for directing pressure from conduit |14 to`either conduit |15 or |16, the other being connected simultaneously to the tank. At the left end of valve |11 is a centering device |18 adapted normally to maintain the valve in a ceny tral or neutral position. In the central position,

thepump |1| is* by-passed to the tank through cent1-al. passageways in the valve |11. A relief valve |19 limits the pressure inthe conduit |14. At the right end of the valve |11r extends a rod into a chamber |8|. 0n this rod is a piston The pilot pump |12 delivers pilot pressure into a conduit |85 and thence to a directional control valve |86. This valve is to be manually operated 'by a lever |81. Two conduits |88 and |89 connect the valve |86 with opposite sides of piston 82 in chamber |8I. When the'valve |86 is'in the position shown in Fig. 17, pilot pressure may be directed to piston |82 through the conduit |88 to shift valve |11 to the left as shown. 'When valve |86 is moved to the position shown in Fig. 19, pilot pressure is then exposed to conduit |89 and the: left side of piston |82 so 4that valve4 l|11 will be shifted to the, right and reversal ofthe motor Valve |86 also has a neutral position as shown in Fig. 18. In this position, both ends of piston |82 are'vented to the tank through conduit |90, thus allowing valve |11 to l 'be returned to neutral by its centering spring.

In this manner, the flow from pump |1| is diverted to tank and the motor stops.4 It will be further noted that when valve |88 isl in the position shown in Fig. 18, pressure conduit |4| is also vented to the tank. Conduit |90 connects two ports of valve |86 to the tank sothat when one end of the cylinder |8| is connected to pressure, the other end will be connected to the tank.

A check valve |85a is placed in line 85 to relieve the pump |12 after piston |82 is shifted and valve |88 is ina position shown either in Fig. 17 or 19.

So far there has been described in Fig. 17, a pilot operated directional control valve with a pilot valve for operating the same. Referring now to the timing control, it will be seen that leading from conduit |88 is a conduit |9| which opens to a port surrounding a valve |92. Simi larly, leading from conduit |89 is a conduit |93 leading to a port surrounding a valve |94. Between the valves |92 and |94 is a conduit |95. Leading from valve |94 to a. third timing control valve |96 is a conduit |91. Each of the valves |92, |94 and |96 is provided with followers whichl .ride respectively on cams |98,|99 and 200. Cams |98 and |99 are each connected to a motor shaft 20| on motor |13 in such a way that they will make one revolution for a predetermined number of revolutions of the shaft 20|. Cam 200 is connected to shaft 20| in a'one to one ratio so that cam 200 revolves once for every revolution of shaft 20|.

As the parts are shown inv Fig. 17, the motor is completing a movement in one direction. Cam |98 has just shifted valve |92 upwardly so that conduits 9| and |95 are connected to conduit |91 which is blocked by valve |96. A slight further movement of shaft 20| in its present direction will move c 200 so that valve |96 will be shifted to the p sition shown in Fig.` 20.

By reason of this movement, the right side of piston |82 will be connectedgto the tank through vconduits ls, |9|, |95, |91 and a tank une 202.

This venting of the right side of piston |82 will allow the centering device to-move valve |11 to neutral position. i When movement of motor |13 in the other direction is desiredthe lever |81 'must be moved to the position shown in Fig. 19. Pilot pressure will then be directed from conduit |85 to conduit left side of' piston |82 and cause a return of valve |81 to neutral. VThe brake is provided on the shaft 20| as described in connection with Fig. 13. A conduit |4| leads from the pressure conduit v|85 to 4pistn |39 which controls a brake member |38 moved by-spring |40 to braking position with a drum |36 on shaft 20| when pressure in |4| is relieved.

The gear ratio of drive for cams |98 and |99 is the same but these cams are arranged out of phase with each other so that valves |92 and |94 are not opened at the same time. This permits each of the valves |92 and |94 to cooperate individuallywith valve |96. v

vIn Figs. 21 and 22 the invention is illustrated in connection with a hydraulic system which utilizes a variable displacement pump as a source of pressure. This pump, shown at 205, has a tilting block 206, the position of which controls the output of the pump. A motor 201 drivesthis pumpand also, through gear train 208, drives a pilot pump 209. A relief valve V2|0 is provided in va conduit 2|| leading from the pump 205 to a motor 2|2.` Another conduit (not shown) is. Proi 225 temporarily.

movement of a member.

` a conduit 211 to chamber 215. When this pilot pressure is maintained against piston 214, there will be a volume output of pump 205 and a movement of motor 212. A venting of this pilot pressure to the tank will cause the spring to move the tilting block 206 to its neutral position and cause a stopping of the motor. The pilot pressure is controlled by a timing valve 218 and a timing valve 219. The valve 218 has a follower which rides on a cam 220 which rotates once in a predetermined number of revolutions of a shaft V221 n motor 212. Valve 219 has a follower which rides on a cam 222 which rotates once for every revolution of shaft 22|. Conduit 217 is connectedl to valve 218 by a conduit 223 and with valve 212 in the position shown in Fig. 21, the conduit 223 is connected to a conduit 224 leading to valve 219. With valve 219 in the position shown, conduit 224 is blocked from a tank conduit 225 but a movement of valve 219 to the position shown in Fig. 22, will connect conduit 221B to the tank conduit 225.

Referring now to the operation of this system of Fig. 21, it will be seen that as the parts are viewed in the drawings, cam 220 has just shifted valve 218 to connect conduits 223 and 22d. 'As cam 222 completes its revolution and moves'to a position shownin Fig. 22, valve 219 will be lifted and there will be a venting of pressure in chamber 215 through 'the conduits shown tothe tank conduit 225. In Fig. 22, the valve 218 is shown in its closed position as it normally rides on cam 220 and valve 219, as before mentioned,

is shown in its open position. To start the system, after it has been automatically stopped, a manually operable lever 226 may be used to shift valve 219 upward to block the tank conduit As soon as valve 219 rides o the lobe of cam 222, the manual lever 226 may be released since conduit 224 will be caused to be blocked from conduit 225 by the spring of valve 219 moving it downwardly as shown in Fig. 21. Blocking of conduit 224 will, of course. cause pressure to build up in chamber 215 and start the volume output of pump 205. Just before cam 222 completes its first revolution, the lobe of cam 220 will have advanced to a point where it allows valve 18 to lower and block conduit 223. A brake similar to that showm in Figs. 13 and 17 is also shown in connection with Fig. 21.

In each of the above modifications, embodying the invention, the object is to achieve accurate control of a moving member.v In each of the above illustrations this has been accomplished by arranging the timing control valves so that they are responsive in a different degree to the The invention has numerous applications. It mightalso be arranged to control a member having longitudinal movement, suitable connections being provided be tween the timing valves and the member.

Iclaim: .1: In a power system including motor means tobe operated in a predetermined cycle, a coning a plurality of trol circuit for said motor means including a pressure control line operatively connected to said means, and arranged, when open, to stop said power system, a counter-valve in said line connected to said means in a manner to be operated once during said cycle, and a tripper valve in said line connected to said means in a manner to be operated a predetermined number of times in said cycle, each of said valves being connected in series in said line and arranged, when simultaneously operated, once in each cycle, to open said line.

2. In a hydraulic control system, a hydraulic motor, a source of fluid pressure therefor, a source of pilot pressure, means responsive to said pilot pressure for controlling the movement of said motor, and means for controlling said pilot pressure comprising a plurality of valve means in series hydraulically, means operating said valves a different number of times relative to a predetermined movement of said motor, said valves being arranged to operate simultaneously at the end of a predetermined movement of the motor and cooperating to influence the effect of pilot pressure on said first named means after said predetermined movement of said motor.

3. A timing device for accurately measuring and limiting the operating cycle in a hydraulic transmission system comprising a hydraulic motor intended to have a predetermined cycle of operation, a source of iluid pressure for said motor, and means for determining the cycle of operation of said motor comprising a plurality of valve means actuated by motor movement, operatively connected to a controll circuit for said motor, and cooperatively arranged to have anefiect on said control circuit when correspondingly positioned, one valve means being operated relatively slow and the other or others being operated faster whereby at a predetermined point in the movement of said motor, the valves will each be correspondingly positioned to affect 'said circuit to change the movement of said motor.

4. A timing device for accurately measuring and limiting the operating cycle in a hydraulic transmission system comprising a hydraulic motor and'output shaft therefor, intended to have a predetermined cycle of o ation, a source of uid pressure for said mot means for con'- trolling the movement of said motor, and means in a, control circuit for said motor comprising a plurality of valve means in series in a pressure line, each adapted in a certain position to have the same effect on said line, and means operatively connecting said valves and said .o utput shaft arranged to operate said valves at different speeds and arranged at a predetermined point in the cycle of movement to position said valves to have said corresponding effect on said line and to change the movement of said motor.

5. In a hydraulic control system, a motor, a. source of pressure, means to control said pres,- sure and the movement of said motor comprisvalve means, each responsive to a different degree to the movement of said mOtOr and cooperating at a predetermined point in the movement of said motor to influence the eiect ofsaid pressure on said motor whereby ,the movement of saidmotor may be accurately controlled.

6. In a hydraulic control system ,a motor, a source of pressure for operation of said motor, a source of pilot pressure, means responsive to said pilot pressure for controlling the movement of said lmotor, and means for controlling said pilot ypresr named means and each movable to a position l whereby they cooperate to Vcontrol the eiect of said pilot pressure on said responsive means, each of said valve means being responsive in a, dilferent degree to the movement of saidl motor and each arranged to be shifted. at a predetermined point in the movement of said motor, to va position whereby the effect of pilot pressure on said first named meansis changed.

'7. In a hydraulic control system, a motor, a source of pressure, means for controlling said pressure and the movement of said motor comprising a ilrst control valve connected to said pressure, a second control valve movable to an open position to direct pressure from said first valve to a tank, said first valve being movable from a closed position to an open position connecting said pressure with said second valve, and means connecting said motor with said .valves whereby movement of said motor will cause movement of saidn valves, said connecting means being so arranged that at a predetermined point in the movement of 'said motr,'each of said valves will be in open position to render said pressure ineffective to operate said motor.

8. In a hydraulic control system, a source of pressure, a motor to be operated by pressure from saidsource, a source of pilot pressure, means for controlling the movement of said motor comprising a motor control valve in the exhaust of -said motor shiftable from a closed position in l a pilot line directing pilbt pressure to said motor control valve to shift the valve to the other of its positions, a bypass line leading from said pilot line adapted, when open, to render said pilot pressure ineffective to shift said motor control' valve, and a plurality of valve means in said bypass line each movable from a position closing l said line to an open position, and means connecting said motor with said valve means where-v by movement of said motor will shift said valve means to open position at varying intervals. said connecting means being so arranged that ata predetermined point in the movement of said motor, the pilot pressure in said bypass line will be influenced thereby thus permitting said motor control valve to shift to closed position.

9. In a hydraulic control system. a source of pressure, a motor to be operated by pressure from said source, a source of pilot pressure, means for' controlling the movement of said motor comprising a motor control valve in the. exhaust of said motor shiftable froma closed position in which said exhaust is blocked to an open position in which said exhaust is free, means urgingsaid motor control valve to one of its positions, a pilot line directing pilot pressure to said motor controlwalve to shift the valve to said`control valve.

vexhaust of said motor shiftable' from a closed position in which said exhaust is blocked to an open position in which said exhaust is free, means urging said motor control valve to one of its positions, a pilotfline for directing pilot pressure' to said motor control valve to shift the valve to the other of. its positions, a bypass line leading from saidpilot line adapted, when open, to render said pilot pressure ineffective to shift said motor control valve, and a plurality of valve means in said bypass line each movable from a position"closing said line to an open position, and means connecting said motor with said valve means whereby movement of said motor will shift said valve means to open position at varying intervals, said connecting means being so arranged that at a predetermined point in the movement of said motor, the pilot pressure in said bypass `line will be iniluenced thereby thus permitting said motor control valve to shift to closed position, and releasable means for locking said motor at a predetermined point in its movement, said releasable means being operable when said pilot pressure is so influenced as to permit the closing of -1, 1 In a hydraulic control system, a source of pressure, a. motor to be|operated by pressure from said source, a source of pilotpressure, means for controlling the movement of said motor comprising'a motor control valvein the exhaust of said motor shiftable from a closed position in which said exhaust is blocked to an open position in which said exhaust is free, means urging said motor control valve to its closed position, means for directing pilot pressure to said motor control valve to shift the valve to open position, a ybypassline leading from said pilot line adapted, when open, to render said pilot pressure ineffective to shift said motor control valve, and a plurality of valve means in said bypass line each movable from a position closing said line to an open position, means connecting said motor with said valve means whereby movement of said motor will shift said valve means to open position at varying intervals, said connecting means being so arranged that at a predetermined point in the movement ci?` said from said source, conduit means for directing pressure from said source to said motor, valve means shiftable from a closed position to a posithe other of its positions, a bypass line leading l from said pilot line adapted, when open, to render said pilot pressure ineiective to shift said motor control valve, and a plurality'of valve means in said bypass lineeach responsive to a different degree to the movement of saidv motor and cooperating at a predetermined point in the movement ofsald motor to influence the effect ci pilot pressure on said first named means whereby the movement of said motor may be accurately controlled. L

10. Ina hydraulic control system, a source of tion wherein said pressure source is bypassed, a pressure chamber: behind said valve means, a source of pilot pressure connected to said pressure chamber'- and normally urging said valve means to its closed position, and means for controlling said pilot pressure comprising a plurality'of movable valve means each shiftable at a different rate' by the movement of said motor and'cooperating'at a predetermined point in the movement of said motor to bypass said pilot pressure and relieve said pressure chamber thereby permitting pressure Ifrom said source to bypass.

13. In a hydraulic control system, a source of pressure, a motor to be operated by pressure from said source, conduit means for directing pressure from said source to said motor, valve means shiftable from a closed position to a position wherein said pressure source is bypassed, a pressure chamber behind said valve means, a source of pilot pressure connected to said pressure chamber and normally urging Asaid valve means to its closed position, and means for controllingfsaid pilot pressure comprising a plurality of movable valve means each responsive to a different degree to the movement of said motor and cooperating at a predetermined point in the movement of said motor to bypass said pilot pressure and relieve said pressure chamber thereby permitting pressure from said source 'to bypass, and releasabl'e means for locking said motor at a predetermined point in its movement, said means being rendered effective by the relieving of said pilot pressure from said pressure chamber.

` 14. In a hydraulic control system, a source of pressure, a motor to be operated by pressure from said source, conduit means for directing pressure from said source to said motor, valve means shiftable from a closed position to a position wherein said preaire source is bypassed, a pressure chamber behind said valve means, a bypass line leading from said pressure chamber adapted,

when open, to render said pilot pressure ineiecl tive to maintain said valve means in closed position, and a plurality of valve means in said bypass line each movable from a position closing said line to an open position, and means connecting said motor with saidvalve means whereby movement of said motor will shift said valve means to open position at varying intervals, said connecting means being so arranged that at a predetermined point in the movement of said motor, said bypass line will be open, thus relieving said pressure chamber and permitting pressure from said source to bypass.

15. In a hydraulic control system for auto matically oscillating a movable member in cycles, a motor to aetuate 'said movable member, control means to control the direction of movement of said movable member, a source of pilot, pressure, conduit means connecting said pilot pressure with said control means whereby the control means may be shifted by said pilot pressure, a directional control valve means in said conduit means adapted at one .position to admit pilot pressure to shift said control means to one position and adapted in a second position to shift said directing valve to another position, a timing control valve in said conduit means shiftable from a. closed position to an open position to admit pilot pressure to said directional control valve, and means operatively connecting said movable memvber with said timing control and said directional control valves whereby at a predetermined point in the movement of said movable member, pilot pressure will be directed to said control means to shift the same and thereby change the direction of movement of said motor.

16. In a hydraulic control system for automatically oscillating a rotating member in cycles, a motor to. actuate said member, control means for controlling the starting and direction of said member, a source of pilot pressure, pressure responsive means for operating said control means,

.conduit means connecting said pressure responsive member with said pilot pressure whereby the pressure responsive member may be inuenced by said pilot pressure to control the direction of movement of said motor, and control means for controlling pilot pressure to said pressure responsive means comprising a rst valve means in said conduit means shiftable to two positions to direct pilot pressure, respectively, to opposite points to cause movement in opposite directions of said motor, a second valve in said conduit means movable from a closed position blocking pilot pressure to an open position admitting said pilot pressure to said rst valve, and means connecting said movable member and said rst and second valves being so arranged that said iirst valve is shifted from one position to another during a predetermined number of revolutions of said movable member, and said second valve is moved to open position once in every revolution of said movable member whereby said movable member is reversed in direction-at a predetermined point in a revolution and after the elapse of predetermined number of revolutions in either I A comprising a control line, two valves in series in said line, each movable to a closed position closing said line and to an open position opening said line, a memberto be rotated by said motor and means operably connecting said member and said valves, said connecting means being so arranged that one of said valves is moved to open position once in every revolution of said member and the other of said valves is moved to open position only upon a predetermined number of revolutions of said member whereby at a predetermined point in a revolution, after the elapseof .a predetermined number of revolutions, said pilot pressure will be bypassed and the operation of said motor will be changed.

18. In a hydraulic system, a rotatable motor, a source of uid pressure for said motor, a source of pilot pressure, means responsive 'to said pilot pressure for controlling the movement of said motor, and means for iniiuencing said pilot pressure to control its effect on said rst named means comprising a control line, two valves in series in said line, each movable to a closed position closing said line and to an open position opening said line, a member to be rotated by said motor and means operably connecting said member and said valves, said connecting means being so arranged that one of said valves is moved to one of its positions once in every revolution of said member and the other of said valves is moved to a corresponding position only upon a predetermined number of revolutions of said member whereby at a predetermined point in a. revolution, after the elapse of a predetermined number of revolutions, said pilot pressure will be inuenced and the operation of said motor will be changed. f

HARRY F. VICKERS. 

